The invention concerns devices for applying therapeutic traction to the digits of the extremities (hands or feet) and, more particularly, to devices which are self-contained, thus maintaining patient mobility.
Traction systems and devices according to the invention may be applied to the digits of both hands and feet but for convenience the following discussion will be limited to the hand application.
Traction is indicated and potentially beneficial for a number of health conditions, including arthritis, and many devices are available.
Certain non-malignant conditions, such as arthritis, repetitive motion injury, trauma and the like, cause unnatural pull on the muscles, tendons and ligaments of the hand resulting in painful joints, deformities and sometimes partial or total loss of use of the hand. Pain, loss of joint strength and range of motion may be experienced because a phalanx drifts or is pulled out of its normal position in relation to another phalanx or the metacarpal bone, causing the respective joint to become deformed. Or the phalanges and metacarpals of the hand may partially degenerate as a result of disease and the like, resulting in deformities (misalignment) or distortions of the hand.
Devices which apply an axial force (traction) across a joint tend to:
1) Lower the pressure within the joint, resulting in pain relief and an increase in localized blood circulation.
2) Strengthen the muscles, tendons, and ligaments.
3) Restore the joint's normal range of motion.
4) Act as an opposing force to undesirable joint contractive forces which can cause deformities.
5) Facilitate the healing process.
Application of a static tensile force to a digit requires, of course, a tension member which is fixed at both ends, one end connected to the digit and the other end anchored at a point fixed in relation to the point of attachment to the digit. In some devices this anchor or reaction point of the tension member may be remote from the hand on another part of the body or for example on the frame of a bed supporting the patient. In devices which may be classed broadly as self-contained the anchor point is on the hand and/or wrist. Self-contained devices are potentially more compact and provide greater mobility for the patient.
The present invention is related to the self-contained group. Known devices in this class tend to be complex, requiring skilled application and custom fitting as well as being heavy and clumsy, offering serious hindrance to the patient's mobility and normal activities. Commonly the ultimate anchoring point is the wrist or forearm so that the whole hand and the wrist itself are encumbered by the traction device. See for example British patents 589,416 Meyer and 620,952 Bolliger and U.S. Pat. No. 4,945,902 Dorer.